BOSTON -- Jackie Bradley Jr. stood in shallow center field bent at the waist, hands on his knees. Under cloud-covered skies at Fenway Park he read balls off a fungo bat, running in every direction to track down flies.

Over-the-shoulder catches, basket catches, he made them all, honing the skill that has allowed him to develop what appears to be a strengthening grip on the job as everyday center fielder for the Red Sox.

Bradley Jr. was deemed the first man out of Boston's big-league outfield group during spring training and was called up just before Opening Day as a sort of emergency measure. Shane Victorino had been slowed by a hamstring injury and the Red Sox needed a body.

About three weeks later, on Wednesday, the Red Sox had another roster decision to make. They needed bullpen help and had to create room on the roster. Instead of sending the 24-year-old down, the team opted to demote fellow outfielder Daniel Nava.

With Victorino set to return at some point this week, possibly as early as Thursday, it appears as though Bradley Jr. has secured his spot on the roster. At least as long as Nava continues to re-discover his swing in Pawtucket.

What might be viewed as a minor victory for Bradley Jr. -- he avoided the demotion that he couldn't escape coming out of spring training -- wasn't perceived as such.

"I don't really focus too much on that," Bradley Jr. said when asked if Wednesday's roster move allowed him a sigh of relief. "I obviously want to be here and help the team out as much as I can. That's my goal."

What's allowed Bradley Jr. to experience some success in his second go-round in the big leagues (he started last season in Boston after a scorching spring training) is his focus on the here-and-now. Any big-picture message he could have taken from the decision for him to remain with the Sox got lost in the shuffle as he focuses on his everyday duties.

"I'm just focused on the simple things," he said. "Who's pitching tonight? Getting ready for the game. I really don't worry about anything else. I worry about what I can control and family. Go out there and do the best I can. It's still April, there's a lot of season left. Trying to be ready throughout the whole season."

Bradley Jr. is still adjusting to major-league pitching as his .228/.333/.298 slash line would suggest. He has also peen punched out 19 times in 66 plate appearances -- a 28.8 strikeout percentage.

But his defensive ability has been a revelation. He has excelled in Fenway Park's expansive right field, but the team values him more highly as a center fielder. He's played exclusively in center in his last 11 games.

The Red Sox have all but admitted that Bradley Jr. is their best option there. Whereas he battled newcomer Grady Sizemore for the spot in spring training, that positional competition appears to be over. Sizemore has been tested at corner outfield spots of late, and that appears the team's plan for him going forward.

"Through repetition, we see him more as a corner outfielder at this point than in center field," manager John Farrell said of Sizemore, "so we're doing what we can to shorten down that curve to be more efficient."

Bradley Jr. has been more than a suitable alternative in center; he's been dazzling at times. Not only because of the jumps he gets and balls he tracks down, but he's also displayed impressive arm strength.

"I think we're just seeing him more regularly here," Farrell said. "You're seeing different plays be made. I think you're getting a better read on what his arm strength is and how that plays. I can't say he's taking it to another level. I think we're seeing him make more plays than we did a year ago."

And the Red Sox believe he's only getting better.

"Oh I think he'll definitely improve," Farrell said. "Particularly with his throwing accuracy. That's a point of emphasis that continues to be stressed. He's got very good arm and yet it can be a little erratic at times. It's something he's aware of and something that we continue to address with him. I think he's an above average center fielder that will have the ability to impact or the potential to impact every game in which he plays defensively."

That Bradley Jr. continues to play in the big leagues as the roster is shaken up speaks volumes of the trust the Red Sox now have in him.

"Despite being sent out of camp, he's still remained a confident player," Farrell said. "As he came back to us, as he's been a regular in our lineup, I think he's gained comfort. If there was any lack of confidence, that's been regained. He's put up good at-bats, and I think relatively consistent at-bats. Defensively . . . he's had an impact every time he's been on the field."

Before Wednesday's game with the Yankees, Bradley Jr. remembered what he told himself when he was called up for Boston's opening series with the Orioles in Baltimore.

"I was just saying it's just another opportunity," he said. "Opportunity presents itself, try to take full advantage of your opportunity. Ball's left in your court."

He's snagged that one, too, and earned the right to stick around.

Phil Perry serves as a general reporter for Comcast SportsNet, mainly covering the New England Patriots. Follow Phil on Twitter here.